University of auckland, Cary Institute
University of auckland
Manaaki Whenua - Landcare Research
2025-11-18
Proxy data are the product of multiple sources of uncertainty
Virtual ecology (Zurell et al. 2010)
Pseudoproxy experiments (Mann and Rutherford 2002)
Proxy system modelling (Evans et al. 2013)
Other key refs:
Virtual ecology is a framework for assessing sampling and analytical methods in simulation consisting of:
An ecological model that generates synthetic data
1a. a degradation model
A simulated observational process (a sampling model) that samples the synthetic data
An analytical process or statistical model applied to both sets of data
An assessment of the results
Borrowing the term “pseudoproxies” from climatology:
The process by which environmental change is recorded as an observable signal in an archive:
Let’s follow a singe replicate case-study
We set out to:
Ok, now we have generated the data, let’s analyse it. Two analyses:
Demonstrating two scenarios with different driving environments
Pervious slides followed:
Each replicate results in 1210 datasets from the ‘error-free’ to the most uncertain 😱
Across replicates for each of the 1210 datasets:
Extract features from the FI and PrC
Calculate the distance between each dataset from the ‘error-free’ to the most uncertain
Make cool visulisations!
Simulation methods can be integrated with empirical studies to:
a priori help shape field sampling methods: e.g., number of core samples (across a region or local replication) required for a given research question
understand the sub-sampling and count resolution required to increase the likelihood of detecting a hypothesised signal in the data
accompany empirical study to test hypotheses about the underlying dynamics that may cause an observed pattern in the data
assess whether inferences made from the data are robust to uncertainty
“All models are wrong, some are useful” Box (1979)
George Perry (University of Auckland)
Janet Wilmshurs (Manaaki Whenua – Landcare Research)
Jack Williams (University of Wisconsin Madison)
Tony Ives (University of Wisconsin Madison)
Biological heritage Science Challenge (NZ) and the National Science Foundation (USA)